Many industrial processes use vapor-liquid separation devices to remove liquid droplets from a vapor stream. For the purposes of this application, the terms “vapor” and “gas” are used interchangeably. In mass and/or heat transfer equipment, liquid droplets are often generated through vapor-liquid contacting or phase change. An example of one such process is co-current fractionation wherein a generally downward flowing liquid phase contacts an upward flowing vapor phase. Although the overall flow of vapor and liquid in this process is counter-current, the flow of vapor and liquid is co-current when the vapor and liquid are contacted as the liquid is entrained in the vapor and carried upward to a vapor-liquid separation device wherein the liquid is de-entrained from the vapor. The liquid then flows downward to an inferior stage and the vapor flows upward to a superior stage. Air conditioning systems also commonly require vapor-liquid separation systems to remove water from the cooled air.
One method for de-entraining liquid from vapor is a device which causes the stream to change direction. Because the liquid droplets have a higher density than the vapor of the stream, the momentum of the liquid will tend to make the liquid travel in a straight line and not change direction as quickly as the vapor. The use of various vapor-liquid separation devices at or near the vapor outlet of a variety of process vessels such as flash drums, vapor-liquid separators, receivers, storage tanks, scrubbers, absorbers, and distillation columns is well known in the art.
One such de-entrainment device includes a series of vanes arranged in parallel, each vane being a thin sheet that is formed into hills and valleys. Conventionally, the vanes are spaced apart by spacers to provide a narrow flow path for the stream. The vanes and spacers are often welded or bolted into position, which has a high manufacturing cost in terms of time, skill, and materials. The vapor stream enters one side and takes a zig-zag path to reach the other side. The entrained droplets cannot negotiate the rapid zig-zag and impinge on the vane, where they cling and run down the wall. De-entrainment devices may also include louvers welded to the vanes. The louvers provide pockets that trap and drain liquid and greatly reduce liquid re-entrainment and improve the vapor-liquid separation. The welding, bolting, or otherwise attaching of the louvers, however, increases the complexity of manufacturing.
The vanes and louvers need to be geometrically designed to permit the stream to flow through at a high velocity with a maximum removal of liquid particles from the stream and a minimum pressure drop. As industrial technology has advanced, there has evolved an increasing demand for eliminators which operate at high velocities, with a high efficiency level, and a minimum pressure drop.
A variety of such vapor-liquid separation devices are taught for example by U.S. Pat. Nos. 4,802,901; 5,296,009; 3,912,471; and 6,852,146. Therefore, what is needed is a vapor-liquid separating device having a simplified structure and assembly. Eliminating the need for additional components and/or steps such as spacers fastening or welding to at least partially define the fluid flow paths is also desirable.